@media (max-width: 720px) {
    .site-header__inner {
        flex-direction: column;
        gap: 0.75rem;
        align-items: flex-start;
    }

    .main-nav a {
        margin-left: 0;
        margin-right: 1.25rem;
    }

    .product-detail__grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .product-gallery__main {
        max-height: 45vh;
    }

    .gallery-thumb-btn {
        width: 52px;
        height: 52px;
    }

    .gallery-arrow {
        width: 30px;
        height: 30px;
        font-size: 0.95rem;
    }

    .lightbox-close {
        top: 0.5rem;
        right: 1rem;
    }

    .size-btn {
        min-width: 40px;
        height: 36px;
    }

    .checkout__grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .checkout__summary {
        position: static;
        order: -1;
    }
}